4.2.1

Habitat Niche The area where an organism lives The range of physical and biological conditions in which an organism lives.

E. Symbiosis Any relationship where two organisms are living closely together.

2. Commensalism A symbiotic relationship where one organism benefits and the other is neither benefited nor harmed. Wolf in shade Eyelash mites

3. Mutualism A symbiotic relationship where both organisms benefit mutually. Clown fish and sea anemone Ants and acacia tree

4. Parasitism A symbiotic relationship where one organism benefits and the other suffers. Wasp parasite on caterpillar

Daily Trivia The sidewinder is a desert snake that moves in a way that only 2 parts of it’s body are touching the sand at a time. This prevents the snake from getting burned on the hot sand.

What Shapes an Ecosystem? Photo Credit: ©Michael Fogden/DRK PHOTO

The Niche What is included in a niche? the range of temperatures that an organism needs to survive the organisms place in the food web the time of year it reproduces how many offspring it produces the type of shelter it occupies No two species can share the same niche in the same habitat. Different species can occupy niches that are very similar.

Community Interactions When organisms live together in ecological communities, they interact constantly. Community interactions, such as competition, predation, and various forms of symbiosis, can affect an ecosystem.

Community Interactions Competition- when organisms of the same or different species attempt to use an ecological resource in the same place at the same time.

Competitive Exclusion principle Resources are limited. No 2 species can occupy the same niche in the same ecosystem at the same time. Direct competition will result in a winner and loser. The loser will fail to survive.

Community Interactions The distribution of these warblers avoids direct competition, because each species feeds in a different part of the tree. 18 12 Feeding height (m) Cape May Warbler Each of these warbler species has a different niche in its spruce tree habitat. By feeding in different areas of the tree, the birds avoid competing with one another for food. Bay-Breasted Warbler 6 Yellow-Rumped Warbler

Community Interactions Predation An interaction in which one organism captures and feeds on another organism is called predation. The organism that does the killing and eating is called the predator, and the food organism is the prey.

Antipredator adaptations (crypsis) Disruptive Coloration Animals, like the zebra, use their coloration patterns to make it hard to see them. Counter Shading Counter shading is seen mostly in aquatic animals. They are light on the bottom and dark on the top.

Antipredator adaptations (crypsis) Color Change Some animals can even change their coloring to try and fool predators. Camouflage (appropriate background) Another group of animals look like something commonly in their environment.

Antipredator adaptations (crypsis) Warning Coloration Animals that are poisonous often advertise this by using bright colors and patterns to discourage predators. Mimicry An organism copies the crypsis of another more dangerous organism

4.2.2

DAILY TRIVIA Mount Saint Helens summit was 9,677 feet before the eruption and 8,363 feet after 1,314 feet were removed by the blast.

Ecological Succession What is ecological succession? Ecosystems are constantly changing in response to natural and human disturbances. As an ecosystem changes, older inhabitants gradually die out and new organisms move in, causing further changes in the community.

D. Ecological Succession Predictable changes that occur in a community over time. Primary Succession No exposed soil Pioneer Species The first species to populate a new area.

Ecological Succession The gradual, sequential re-growth of a species in an area Sometimes, an ecosystem changes in response to an abrupt natural or man-made abrupt disturbance. At other times, change occurs as a more gradual response to natural fluctuations in the environment.

Ecological Succession Pioneer Species The first species to grow after an ecological disturbance. tend to be small, fast growing and fast reproducing Each stage of succession alters the physical environment in ways that make it less favorable for their own survival but more favorable for the organisms that will replace them Climax Community A stable, mature community that marks the “end” of succession.

Ecological Succession In this example, a volcanic eruption has destroyed the previous ecosystem. Primary succession occurs on newly exposed surfaces, such as this newly deposited volcanic rock and ash.

Ecological Succession The first organisms to appear are lichens. Primary succession occurs on newly exposed surfaces, such as this newly deposited volcanic rock and ash.

Ecological Succession Mosses soon appear, and grasses take root in the thin layer of soil. Primary succession occurs on newly exposed surfaces, such as this newly deposited volcanic rock and ash.

Ecological Succession Eventually, tree seedlings and shrubs sprout among the plant community. Primary succession occurs on newly exposed surfaces, such as this newly deposited volcanic rock and ash.

Ecological Succession Secondary Succession Occurs where an existing community has been cleared by a disturbance, natural or man-made, but the soil has been left intact. What would be some examples of disturbances that would result in secondary succession?

The Eruption of Mount Saint Helens http://www.youtube.com/watch?v=rbgAOfv-W20

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